Tank winding and prestressing apparatus

ABSTRACT

In wrapping wire around a concrete tank to prestress the same, a motor-driven carriage travels around the tank with a sprocket wheel engaging a chain that extends around the tank. Simultaneously, the wire is fed from a supply spool onto a wire gripping drum and is then laid on the outer tank wall with a wire tension established by the difference in peripheral lineal speed between the sprocket wheel (carriage speed) and the gripping drum. This difference in speed stretches, i.e., tensions the wire. Means are provided for sensing the difference in such speeds and to provide for changes in such difference such that the wire may be uniformly stressed when and as it is being laid on the tank.

"United States Patent Dykmans *July 1, 1975 [54] TANK WINDING AND PRESTRESSING 2,573,793 ll/l95l Kennison 242/722 2,589,366 3/1952 Gauthier 242/722 APPARATUS 3,379,385 4/1968 Osweiler 242/722 [76] Inventor: Maximiliaan J. Dykmans, 4434 3,397,850 8/1968 Anderson 24217.22

Mayaxan Dr., La Mesa, Calif. 92041 Primary Examiner-Billy S. Taylor 1 Notice: The portion of the term of this Attorney, Agent, or Firm-Lyon & Lyon patent subsequent to Mar. 30, 1988. has been disclaimed. [57] ABSTRACT [22] Filed: June 2, 1973 Appl. No: 375,452

Related US. Application Data Continuation of Ser. No. 105,056, Jan. 8. i971, abandoned. which is a continuation of Ser. No. 7l8,464, April 3, I968, abandoned,

US. Cl. 242/7.22 Int. Cl B2lf 17/00 Field of Search 242/721, 7.22, 7.23, 7.02,

References Cited UNITED STATES PATENTS 3/l945 Crom 242/72! X In wrapping wire around a concrete tank to prestress the same, a motor-driven carriage travels around the tank with a sprocket wheel engaging a chain that extends around the tank. Simultaneously, the wire is fed from a supply spool onto a wire gripping drum and is then laid on the outer tank wall with a wire tension established by the difference in peripheral lineal speed between the sprocket wheel (carriage speed) and the gripping drum. This difference in speed stretches, i.e., tensions the wire. Means are provided for sensing the difference in such speeds and to provide for changes in such difference such that the wire may be uniformly stressed when and as it is being laid on the tank.

8 Claims, 7 Drawing Figures 5 Twp a5 59 g 88 Q g I05 7? /07 g 75 2 M M sat/W2 54 i 75 an 2 e l g m lea g 5 ,.7//// I 5 55 ///////1 I l 1 TANK WINDING AND PRESTRESSING APPARATUS The present application is a continuation of my copending application, Ser. No. 105,056 filed .Ian. 8, 1971, which in turn is a continuation of my application Ser. No. 7 l 8,464 filed Apr. 3, I968, both of said applications Ser. Nos. 7 [8,464 and I05,056 having been abandoned without, of course, abandoning the invention disclosed therein.

The present invention relates to improved means and techniques and is particularly useful in the prestressing of concrete structures such as, for example, reservoirs, nuclear reactor housings, pipe and pressure vessels in general although it has wider applications in, for example, the laying of cable.

A specific object of the present invention is to provide improved means and techniques whereby wire, strand or cable may be laid circumferentially on the structure with uniform stress.

Another specific object of the present invention is to provide improved means and techniques having as one of its purposes a monitoring of the difference in the lineal speeds between, on the one hand, the lineal speed of a carriage traveling around the structure and, on the other hand, the lineal speed at which wire, cable, strand or the like is being laid on such structure such that corrections may be made when and as such wire or the like is being laid to thereby achieve a uniform tensioning of the wire or the like.

Another specific object of the present invention is to provide improved means and techniques of this character using means for detecting difference in lineal speed between, on the one hand, speed of a carriage and, on the other hand, rate at which wire or the like is being laid.

The features of the present invention which are believed to be novel are set forth with particularly in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 illustrates a system embodying features of the present invention.

FIG. 2 is a sectional view of a portion of the apparatus shown in FIG. I.

FIG. 3 is a sectional view taken as indicated by the lines 3-3 in FIG. 2.

FIGS. 4 and 5 illustrate the manner in which a carriage travels around a concrete structure while simultaneously wrapping tensioned wire around the same.

FIG. 6 is a schematic diagram of a monitoring circuit which may be used in effecting either manual or automatic adjustment of wire tension.

FIG. 7 illustrates other details of the automatic control.

In prestressing circular concrete structures such as, for example, water reservoirs, nuclear reactor housings and like pressure vessels, wire, strand, cable or the like is wrapped around such structure while simultaneously tensioning the same as it is being so wrapped.

For these purposes, a carriage 10 having wheels 12, illustrated in FIGS. 4 and 5, is caused to move around the concrete structure I I, using a sprocket chain extending around such structure and engaging the following elements on carriage 10 in this order: guides 17 and l8, spring-urged chain tensioning device 20, and sprocket wheels 22 and 14. Sprocket wheel 22 is on the same shaft as a larger pulley 24, which is driven by motor 25 on carriage 10 through a belt or chain 27 to thereby cause the wheeled carriage 10 to travel around the concrete structure in the direction indicated by arrow 30 at a speed established by the speed of motor 25. During such travel the speed of the carriage is metered by a wheel 33 engaging the tank wall II, the peripheral of linear speed of such wheel being a measure of the carriage speed.

During such movement of carriage I0 the wire, cable or strand 34 (FIG. 5) is wrapped around the structure 11, such wire 34 being supplied from a reel (not shown) and passes in turn over a spring pressed roller 36 and drum 38, and between a pair of metering rollers 230, 231 for establishing the linear speed of such wire in that order before engaging the concrete structure 1 l. The drum 38 is rotatably supported on the carriage 10 about an axis which may be coaxial with the rotation axis of sprocket 14 (FIG. 4). This drum 38 may have a sprocket wheel 38A attached thereto so that the same may be controlled by a differential speed mechanism 38B driving a chain 38C passing over such sprocket wheel 38A and a sprocket wheel 38E of mechanism 383. The mechanism 388 is provided with speed control means 38D. The mechanism 388 includes the sprocket wheel 22 and sprocket wheel 14. Because the wire 34 is tensioned and thus stretched, the linear speed of the wheel 33 is somewhat greater than the linear peripheral speed of the metering rollers 230, 231. here is thus a difference in speed depending upon the amount of tensioning, i.e., wire stretch. Conversely the difference in these linear speeds is an indication of the amount of stretch, hence tensioning of the wire. The difference in speed is controlled by the mechanism 388.

It is usually desirable that the wire tension be uniform through the travel and this is accomplished using the system illustrated in FIG. 1 wherein there is a comparison made between the linear speed of the carriage l0 and the linear speed at which the wire is applied to the structure 1 1. For these purposes the lineal speed of the wire corresponds to the peripheral speed of one of the metering wheels 230, 231 which travels with the wire without any slippage therebetween. The lineal speed of the carriage may be represented by the peripheral speed of wheel 33 which engages and travels around the tank without any slippage therebetween. The wheel 33 may be on the end of a pivoted arm 33A which is urged by tension spring 338 to assure this non-slip condition as seen in FIG. 4.

As illustrated in FIG. I, the wheel 33 is on a shaft 52 which through, for example, a flexible shaft 52A, drives a bevel gear 53 meshing with bevel gear 54 on shaft 55. Shaft 55 also mounts a pinion gear 58 and drives an axle gear 60 of a differential system 62. Another axle gear 64 of system 62 drives shaft 73 which mounts a special switch structure 91.

These two axle gears 60, 64 mesh with two or more spider gears 74, 76 each having a shaft about which they rotate, rotatably supported in a large ring gear 80 that circumscribes these two or more spider gears 74, 76.

Ring gear 80 meshes with a gear 84 on the output input shaft 87 mounting a large gear 88 that meshes with the previously mentioned pinion gear 58.

The variable speed drive device 86 may be of the type referred to in the trade as a Dodge Disco unit and incorporates a means such as a hand wheel 89 which may be manually adjusted to correspondingly adjust the ratio of speed to output shaft 85 to the speed of input shaft 87, i.e., speed ratio. Such adjustment as will be described in more detail later is directly related to the speed at which the wire metering wheel 30 turns and hence the tensioning of wire 34.

A coupling device 72 is described relative to FlGS. 1, 2 and 3 and involves two disc like elements 90, 91 each frictionally maintained on its corresponding shaft 71, 73 using a corresponding friction mounting exemplified in FIG. 3. Shaft 71 mounts a bevel gear 70 meshing with gear 68 which is driven by the metering wheel 30. in FIG. 3, shaft 73 is spring-pressed into engagement with a bearing portion of a generally circular insulating element 93 by a metal shoe 94 lined with a friction material 95, such material 95 being pressed against the shaft 73 by coil compression spring 97 to allow some slippage between element 91 and shaft 73 only when an external torque is applied to element 91 as described later. The other element 90 is likewise frictionally mounted on shaft 71 using a spring 101 bearing on shoe 103 to press friction material 105 against shaft 71 so that normally the element 90 rotates with shaft 71 but is allowed to slip on shaft 71 when torque applied to element 90 becomes excessive.

Elements 90 and 91 are in the form of electrical slip rings with brushes 105, 106, 107 contacting conducting rings 109, and 110, 111 respectively circumscribing the corresponding insulating disc element 113, 93 upon which they are mounted. Slip ring 109 is connected to a metal rod or pin 115 which extends laterally into an opening in disc element 93 between two contacts 120, 121 which together with pin 115 may be considered to be elements of a single pole-double throw switch having a neutral position wherein pin or movable switch arm .115 engages neither contact 120 nor contact 121. Contact 120 is connected to slip ring 110 and contact 121 is connected to slip ring 111 using a lateral connecting element (not shown) like that shown in FIG. 2 wherein pin 115 extends laterally to provide a connection to slip ring 109.

One function of the coupling 72 is to establish different conditions depending upon whether (1) shafts 71 and 73are turning at the same speed (2) shaft 71 is turning faster than shaft 73 or (3) shaft 71 is turning slower than shaft 73. These conditions may be established using the switch construction described and it will be appreciated that in accordance with the teachings herein other means may be used to establish such conditions as, for example, the pin 115 may be used to actuate microswitches having contacts connected to slip rings.

In its simplest form the single pole double throw switch described may be used to provide a visible indication as in FIG. 6 wherein the movable switch arm 115 is connected to the ungrounded terminal of voltage source 130 and the contact 120, 121 are connected respectively to the ungrounded terminals of indicating lamps 133, 134. An operator then may be guided by such illuminated indications (or lack ofillumination) to manually adjust the speed at which the wire gripper drum 38 is rotated by differential speed mechanism 3813 which has suitable differential speed control knob 38D for that purpose.

In such case the operator monitors the condition of lamps 133, 134 and adjusts the differential speed control knob 38D to cause both lights to be deenergized, i.e., unlit. In doing so, difference in speeds is maintained substantially constant and hence the wire is wound under substantially constant tension.

When it is desired to change the nominal tension at which wire is to be wound, the operator first adjusts the handwheel 89 to provide a different tension setting after which he again adjusts the speed control means 38D as before to minimize the time during which either one of the two indicating lamps 133, 134 is lit.

In more sophisticated arrangements as also contemplated herein, the differential speed control means 38D may be adjusted automatically using a servo system 140 responsive to the condition of the single-pole doublethrow switch 115, 120, 121 to adjust the speed of the wire drum 38 such that whenever the switch arm contacts one of the contacts 120, 121 the switch arm is restored to its neutral condition which corresponds to equal speeds of shafts 71, 73.

it will be appreciated that the differential speed mechanism 388 controls directly the speed of the wire drum 38 in relation to the speed of the chain drive sprocket 14 and hence directly regulates the differential speed of travel of carriage 10 around the tank and wire feed out. This differential speed control may be obtained using a differential hydraulic system, differential gear or variable gears as described in more detail in my copending patent application, Ser. No. 718,138 filed Apr. 2, 1968 now U.S. Pat. No. 3,572,596.

The servo system may control the speed ofa ring gear in a differential system such that when switch 115, is closed such ring gear travels faster and when switch 115, 121 is closed the ring gear travels slower. For this purpose, the ring gear may be driven by a motor including conventional speed control means which may include adjustable means for adjustment of its nominal speed. This adjustment and control may, for example, be accomplished in the field circuit of a DC. motor as exemplified in FIG. 7 wherein the ring gear 200 is driven by a motor 201 having a terminal of its armature 203 grounded and the other one of its terminals connected to one terminal of its field winding 204 having its other terminal connected to one end terminal of tapped resistance 206 having tape 206A, 2063 and 206C. The tap 206B is adjustable to control the nominal speed of the ring gear 200 (the nominal wire tension) and is connected to an intermediate switch terminal 210 (corresponding to the neutral position of switch arm 115). The movable switch arm 212 (corresponding to switch arm 115) is connected to the ungrounded terminal of voltage source 214 and the adjustable taps 206A and 206C are connected to switch contacts 216 and 218 respectively. The ring gear 200 thus controls the relative speeds of sprocket wheels 22C, 38E which may be connected to a corresponding one of two axle gears cooperating with such ring gear 200.

it will be appreciated that the arrangement shown in FIG. 7 is illustrative of other more sophisticated systems which may be used.

The term wire as used herein is used in its broadest sense to include solid wire, strand. cable, either metallic or nonmetallic and the like.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

l. in a system of the character described, a carriage movable on a structure; a wire feeding mechanism on said carriage; a differential system including a first and a second axle gears, a ring gear, spider gear means journaled for rotation on said ring gear and meshing with said axle gears; means for moving said carriage on said structure; means responsive to the speed of said carriage on said structure and coupled to said first axle gear; gear reduction means coupled between said first axle gear and said ring gear to produce a speed of rotation of said second axle gear commensurate with the speed of said first axle gear; means responsive to the speed at which said wire is being laid by said wire feeding mechanism on said structure when said carriage moves on said structure and producing rotation of an element in accordance with the last-mentioned speed; and means comparing the related speed of said element and said second axle gear and producing an output when said relative speed exceeds a nominal value; and means receptive to said output and restoring said relative speed to said nominal value in accordance with said output.

2. A system as set forth in claim 1 in which the lastmentioned means includes a means for controlling said wire feeding mechanism in accordance with said output.

3. A system as set forth in claim 1 in which said comparing means includes switching means a first part of which is mounted for movement with said second axle shaft and a second part of which is mounted for movement with said element.

4. in a system of the character described in which a carriage traveling with respect to a structure mounts a wire feeding mechanism; differential means including a first and a second shaft; means for moving said carriage on said structure; means driving said first shaft at a speed representative of the speed of said carriage; means driving said second shaft at a speed which differs from the speed of said first shaft by a constant amount; means driving a third shaft at a speed representative of the speed at which wire is being laid on said structure; and means comparing the speeds of said third shaft with said second shaft to obtain a comparison; and means controlling said wire feeding mechanism in accordance with said comparison.

5. In a system of the character described wherein a carriage moves around a circular structure when and as wire is being wound under tension around said strucmm, a carriage; means for moving said carriage on said structure; first sensing means on said carriage sensing its speed relative to said structure; wire feeding means on said carriage; second sensing means sensing the speed at which said wire is fed by said wire feeding means to said structure; comparing means controlled by said first and second sensing means and producing an output representative of the difference between said carriage speed and wire feeding speed, said comparing means including a differential system having a pair of axle gears coupled by spider gears, the spider gears being on a ring gear, said first sensing means including a rotatable element being also coupled to said ring gear through an adjustable transmission.

6. A system as set forth in claim 5 in which the other axle gear is coupled to a switching structure and said second sensing means is also coupled to said switching structure.

7. In a system of the character described wherein a wire gripping means and a carriage on which said gripping means is mounted travel around a medium on which wire is laid under tension, means producing relative movement between said carriage and said medium, means monitoring the lineal speed of said relative movement and producing a first quantity representative of the difference in speed between said carriage and said medium, means monitoring the lineal speed at which wire is being laid and producing a second quantity representative of the speed at which said wire is being laid on said medium, means responsive to one of said quantities and producing a third quantity representative of a desired nominal value of the other of said quantities, means comparing said third quantity with said other quantity and obtaining from such comparison deviations from said nominal value, and means responsive to said deviations and restoring said other quantity to a value substantially equal to said nominal value, the comparing means including a servo system and the means responsive to said deviations includes a differential speed mechanism coupled to and controlled by said servo system and having an input shaft coupled to said movement producing means and an output shaft coupled to said wire gripping means.

8. A system as set forth in claim 7 in which manually adjustable means includes a manually adjustable transmission having an input shaft and an output shaft, means coupling said input shaft to one of said monitoring means. a three element differential system, means coupling said output shaft to one element of said three element differential system, means coupling a second element of said three element transmission to said one monitoring means, said means producing said third quantity including a rotatable shaft, and means coupling said rotatable shaft to a third element of said three element differential system. 

1. In a system of the character described, a carriage movable on a structure; a wire feeding mechanism on said carriage; a differential system including a first and a second axle gears, a ring gear, spider gear means journaled for rotation on said ring gear and meshing with said axle gears; means for moving said carriage on said structure; means responsive to the speed of said carriage on said structure and coupled to said first axle gear; gear reduction means coupled between said first axle gear and said ring gear to produce a speed of rotation of said second axle gear commensurate with the speed of said first axle gear; means responsive to the speed at which said wire is being laid by said wire feeding mechanism on said structure when said carriage moves on said structure and producing rotation of an element in accordance with the last-mentioned speed; and means comparing the related speed of said element and said second axle gear and producing an output when said relative speed exceeds a nominal value; and means receptive to said output and restoring said relative speed to said nominal value in accordance with said output.
 2. A system as set forth in claim 1 in which the last-mentioned means includes a means for controlling said wire feeding mechanism in accordance with said output.
 3. A system as set forth in claim 1 in which said comparing means includes switching means a first part of which is mounted for movement with said second axle shaft and a second part of which is mounted for movement with said element.
 4. In a system of the character described in which a carriage traveling with respect to a structure mounts a wire feeding mechanism; differential means including a first and a second shaft; means for moving said carriage on said structure; means driving said first shaft at a speed representative of the speed of said carriage; means driving said second shaft at a speed which differs from the speed of said first shaft by a constant amount; means driving a third shaft at a speed representative of the speed at which wire is being laid on said structure; and means comparing the speeds of said third shaft with said second shaft to obtain a comparison; and means controlling said wire feeding mechanism in accordance with said comparison.
 5. In a system of the character described wherein a carriage moves around a circular structure when and as wire is being wound under tension around said structure; a carriage; means for moving said carriage on said structure; first sensing means on said carriage sensing its speed relative to said structure; wire feeding means on said carriage; second sensing means sensing the speed at which said wire is fed by said wire feeding means to said structure; comparing means controlled by said first and second sensing means and producing an output representative of the difference between said carriage speed and wire feeding speed, said comparing means including a differential system having a pair of axle gears coupled by spider gears, the spider gears being on a ring gear, said first sensing means including a rotatable element being also coupled to said ring gear through an adjustable transmission.
 6. A system as set forth in claim 5 in which the other axle gear is coupled to a switching structure and said second sensing means is also coupled to said switching structure.
 7. In a system of the character described wherein a wire gripping means and a carriage on which said gripping means is mounted travel around a medium on which wire is laid under tension, means producing relative movement between said carriage and said medium, means monitoring the lineal speed of said relative movement and producing a first quantity representative of the difference in speed between said carriage and said medium, means monitoring the lineal speed at which wire is being laid and producing a second quantity representative of the speed at which said wire is being laid on said medium, means responsive to one of said quantities and producing a third quantity representative of a desired nominal value of the other of said quantities, means comparing said third quantity with said other quantity and obtaining from such comparison deviations from said nominal value, and means responsive to said deviations and restoring said other quantity to a value substantially equal to said nominal value, the comparing means including a servo system and the means responsive to said deviations includes a differential speed mechanism coupled to and controlled by said servo system and having an input shaft coupled to said movement producing means and an output shaft coupled to said wire gripping means.
 8. A system as set forth in claim 7 in which manually adjustabLe means includes a manually adjustable transmission having an input shaft and an output shaft, means coupling said input shaft to one of said monitoring means, a three element differential system, means coupling said output shaft to one element of said three element differential system, means coupling a second element of said three element transmission to said one monitoring means, said means producing said third quantity including a rotatable shaft, and means coupling said rotatable shaft to a third element of said three element differential system. 